1. Field of the Invention
This invention relates to a method and system for encoding data prior to transmission of the data to a medium of limited band width, such as a magnetic medium, in order to increase the average number of data bits represented by one signal transition.
2. Description of the Prior Art
U.S. patent application Ser. No. 705,119, filed July 14, 1976 and entitled METHOD AND APPARATUS FOR ENCODING AND RECOVERING BINARY DIGITAL DATA contains a comprehensive summary of the known techniques for recording data on a magnetic medium and encoding systems useful in connection therewith. A similar summary is contained in an article titled "A New Look-Ahead Code for Increased Data Density" by George V. Jacoby and published in the IEEE Transactions on Magnetics, volume MAG-13, No. 5, September, 1977, page 1202 et seq.
Another overview of data encoding techniques for maximizing data storage density on a magnetic recording medium is contained in an article titled "An Optimization of Modulation Codes in Digital Recording" by T. Horiguchi et al and published in the IEEE Transactions on Magnetics, volume MAG-12, No. 6, November, 1976 at page 740 et seq. The Horiguchi article discloses a two-thirds rate code which in implementation is relatively complex because it employs variable word lengths.